Wood preservatives extend the life of the wood and increase durability and resistance to insects and diseases. For example, wood preservatives are used to stop bacterial infiltration into wood structure, which contains numerous pores and channels which act as an easy access route for bacteria and also fungal spores. Wood has been traditionally treated with arsenic containing preservatives, but such arsenic containing preservatives are being phased out from the market due to increased health and environmental concerns. Accordingly, alternative wood treatments such as petrification, heat treatment, and polymer composite formation have been developed. The effectiveness of the newer techniques is inferior to the arsenic-based preservatives. Therefore, better techniques for wood preservation need to be developed.
For effective wood preservation, one strategy includes impregnating the wood cell walls with environmentally benign but highly potent wood preservatives. The development of such typically conflicting properties in a single preservative is time-consuming and difficult. Other strategies may include creating petrified wood (in which silicon dioxide is impregnated into the wood pore) and polymer-impregnated wood composites. For example, sodium silicate (Na2SiO3) may be used as a deterrent against insect attack and possesses minor flame-resistant properties. However, it is easily washed out of the wood by moisture, forming a flake-like layer on top of the wood.
The wood treated with the above strategies may be much heavier than the original wood and the mechanical properties may be very different from the original, including, for example, being harder and more abrasive on tools. Therefore, the usage of wood items treated by these methods may be severely limited. Furthermore, once treated by these methods, the wood often cannot be easily repurposed or recycled. Accordingly, there exists a need for a protective coating for wood which allows the use of the wood for varied purposes and preserves the original wood's physical properties.
Wood preservatives may be used to provide water resistance, antifungal activity, termite control, etc. However, such wood preservatives cannot be loosely loaded into wood at high levels due to environmental leaching. Therefore, there exists a need for a wood coating where a small requisite amount of a wood preservative functional agent coats the wood and is tightly coupled to effectively cover the area in need of a particular agent to prevent leaching.